import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 9)

def main():
    X = int(input())
    if X >= 30:
        print('Yes')
    else:
        print('No')

if __name__ == '__main__':
    main() import sys sys input = sys.stdin.readline input sys.stdin.readline sys.stdin sys stdin readline sys.setrecursionlimit(10 ** 9) sys.setrecursionlimit sys setrecursionlimit 10 ** 9 10 9 def main():
    X = int(input())
    if X >= 30:
        print('Yes')
    else:
        print('No') main X = int(input()) X int(input()) int input() input if X >= 30:
        print('Yes')
    else:
        print('No') X >= 30 X 30 print('Yes') print 'Yes' print('No') print 'No' if __name__ == '__main__':
    main() __name__ == '__main__' __name__ '__main__' main() main input = sys.stdin.readline sys.stdin.readline input def main():
    X = int(input())
    if X >= 30:
        print('Yes')
    else:
        print('No') def main():
    X = int(input())
    if X >= 30:
        print('Yes')
    else:
        print('No') main
import sys
input = sys.stdin.readline
sys.setrecursionlimit(10 ** 9)

def main():
    X = int(input())
    if X >= 30:
        print('Yes')
    else:
        print('No')

if __name__ == '__main__':
    main()
